feat(react): use SSR transform of React Compiler for server envs

[sapphi-red]

Description

Set outputMode=ssr option in React Compiler for server environments.

This has two problems:

• The outputMode=ssr is probably not meant to be public yet. It's not released in babel one (react/react@4cf770d, react/react@50e7ec8)
• consumer=server does not necessarily mean SSR. It may be an environment for RSC.

I found the option so I thought to fix it but found the problems above so I'm opening this PR as draft to discuss about these problems.

[sapphi-red]

The output looks like

import { jsxs as _jsxs } from "react/jsx-runtime";
export function App(t0) {
	const { name } = t0;
	const count = 0;
	return /* @__PURE__ */ _jsxs("div", { children: [name, count] });
}

[hi-ogawa]

Next has something similar and the one in the react compiler isn't likely directly usable (as in it may not be "production ready" for some edge cases).

The agents dug up some history:

• Experimental server optimization vercel/next.js#54925 September 2023. Added optimizeServerReact to remove useEffect/useLayoutEffect and simplify useState in server bundles.
• enable optimizeServerReact by default vercel/next.js#62658 March 2024. Enabled it by default, but disabled the useState optimization because of React 19 compatibility concerns.
• Disable experimental.optimizeServer by default to fix failed server action vercel/next.js#69788 September 2024. Temporarily disabled it because removing effects too early also hid referenced Server Actions.
• Improve the transform and re-enable optimizeServerReact  vercel/next.js#70101 and Use rs minify to replace the optimize cond and fix typo vercel/next.js#70151 September 2024. Re-enabled it by marking effect calls for later dead-code elimination.

Currently it:

• Removes production-server useEffect and useLayoutEffect calls when dependencies have no observable side effects.
• Does not optimize useState, although that implementation remains behind optimize_use_state: false.
• Is enabled by default for production webpack server builds.
• Is not currently wired into Turbopack because its server transform rule is commented out.

[hi-ogawa]

consumer=server does not necessarily mean SSR. It may be an environment for RSC.

In rsc environment, useState/useEffect/etc is a runtime error since they are undefined in react-server exports, so the transform would ideally surfaces the usage error during build time instead like https://nextjs.org/docs/messages/react-client-hook-in-server-component. Rsc plugin currently doesn't do anything (yet).

[ArnaudBarre]

Suggested change

	expect(output.code).not.toContain('useState(0)')
	expect(output.code).not.toContain('useState')